“We've outsourced our manufacturing and much of our pollution, but some of it is blowing back across the Pacific to haunt us.” — Steve Davis, University of California Irvine.

The amount of air pollution from China’s booming manufacturing industry is so great that it is affecting weather patterns across the Pacific in North America, according to a new study published by the U.S. National Academy of Sciences.

The report documents that cities like Los Angeles receive at least an extra day of smog each year from the nitrogen oxide and carbon monoxide that China’s exporting factories generate.

The pollution is also a public health threat and causes other changes in weather, the report cautions.

“The models clearly show that pollution originating from Asia has an impact on the upper atmosphere and it appears to make ... storms or cyclones even stronger,” said Texas A&M atmospheric scientist Renyi Zhang.

He said that the airborne pollution affects cloud formation, precipitation and other factors that are contributing to climate change.

China’s neighbors, Japan and South Korea, have long suffered downwind from where the smog is generated.

This new report shows that the unexpected side effect of the demand for China’s cheap manufactured goods is adversely affecting weather and health half a world away.